JP7194784B2 - Electrolyte material - Google Patents

Description

TECHNICAL FIELD The present invention relates to electrolyte materials containing fluorosulfonylimides, more specifically N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imides and di(fluorosulfonyl)imides, and methods for producing the same.

Fluorosulfonylimides such as N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide and di(fluorosulfonyl)imide and derivatives thereof have an N(SO ₂ F) group or an N(SO ₂ F) ₂ group. It is useful as an intermediate for a compound having a It is a useful compound in various applications such as being used as
At the same time, however, fluorosulfonylimide is a compound from which impurities are very difficult to remove due to its prominent polarity.

Patent Document 1 discloses a method for obtaining a powder by removing the reaction solvent from an alkali metal salt of fluorosulfonylimide, but the problem is that the solvent has a high affinity with the reaction solvent and is difficult to remove. A solvent distillation method that solves the problem is disclosed.

WO2011/149095

However, in the production method described in Patent Document 1, about 1000 ppm of residual solvent (especially the solvent used in the production of fluorosulfonylimide) remains in the alkali metal salt of fluorosulfonylimide. In addition, once the fluorosulfonylimide salt is pulverized, the residual solvent (the above-mentioned manufacturing solvent) is taken into the powder, and its removal is difficult only by drying. For example, when a fluorosulfonylimide salt is used as an electrolyte in a lithium battery, the residual solvent may cause swelling of the battery. Halogen-based solvents, in particular, may corrode aluminum current collectors of lithium batteries due to their decomposition. Therefore, reduction of halogen-based solvents is particularly desired in electrolyte solutions used in batteries for automobiles, which are expected to be used for a long period of time.
The present invention has been made in view of the circumstances described above, and its object is to provide an electrolyte material in which the amount of residual solvent that affects the properties of the electrolyte material is reduced, and a method for producing the same. .

The production method of the present invention that solves the above problems is a method for producing an electrolyte material containing a fluorosulfonylimide salt represented by the following general formula (1) and an electrolyte solvent, wherein the fluorosulfonylimide salt and the electrolyte It is characterized by reducing the pressure and/or heating the solution containing the solvent to volatilize the solvent for producing the fluorosulfonylimide salt.

In general formula (1) above, R ₁ is fluorine or a fluorinated alkyl group having 1 to 6 carbon atoms, and R ₂ is an alkali metal ion. The electrolyte solvent is preferably a cyclic carbonate-based solvent or a cyclic ester-based solvent.

The present invention includes a method for producing a non-aqueous electrolyte, characterized in that the electrolyte material obtained by the above-described production method is further mixed with a solvent for preparing a non-aqueous electrolyte.

Further, the present invention provides an electrolytic solution material containing the fluorosulfonylimide salt represented by the general formula (1) and an electrolytic solution solvent, wherein the concentration of the fluorosulfonylimide salt contained in the electrolytic solution material is 30 mass % or more, and the remaining amount of the solvent for producing the fluorosulfonylimide salt in the electrolyte material is 3000 ppm or less.
In this case, the electrolyte solvent preferably contains 90% by mass or more of the cyclic carbonate-based solvent or the cyclic ester-based solvent.

The present invention also includes a non-aqueous electrolyte obtained from the electrolyte material and an electric storage device provided with this non-aqueous electrolyte.

In addition, the present invention is characterized by storing an electrolyte material containing the fluorosulfonylimide salt represented by the general formula (1) and an electrolyte solvent, wherein the concentration of the fluorosulfonylimide salt is 30% by mass or more. and transporting an electrolyte material containing the fluorosulfonylimide salt represented by the general formula (1) and an electrolyte solvent, and having a concentration of the fluorosulfonylimide salt of 30% by mass or more. Also included is a method of transporting an electrolyte material characterized by:

In the present invention, the fluorosulfonylimide salt, which has been powdered once and the residual solvent has been taken into the powder, is dissolved by adding the electrolyte solvent to form a solution, so that the residual solvent easily volatilizes. Also, since the electrolyte solvent has a higher affinity for the fluorosulfonylimide salt than the residual solvent, the residual solvent can be efficiently removed by reducing the pressure and/or heating. Moreover, the obtained solution can be used as it is as an electrolytic solution material. In addition, the present invention is not limited to removing the residual solvent from the powder, and the solution in which the fluorosulfonylimide salt is dissolved in the residual solvent can be similarly treated by adding the electrolyte solvent and depressurizing and / or heating. Residual solvent can be removed.

According to the present invention, an electrolyte material containing N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide and di(fluorosulfonyl)imide with reduced residual solvent that affects the properties of the electrolyte material is provided. can get. In addition, since the electrolyte material is a liquid, there is no need for equipment for handling highly hygroscopic fluorosulfonylimide salt powder, so production costs can be reduced. Furthermore, since the non-aqueous electrolyte can be obtained by using the electrolyte material of the present invention as it is or by simply diluting it, the workability is improved, and the non-aqueous electrolyte can be produced inexpensively and simply. In addition, by preparing a liquid electrolyte material in advance, an effect of suppressing heat generation (heat of dissolution) when mixing the fluorosulfonylimide salt powder with the solvent for the electrolyte is exhibited. Furthermore, the electrolyte material of the present invention also has the advantage of generating a small amount of HF when stored in a solution state.
Further, an electrolytic solution containing a fluorosulfonylimide salt represented by the above general formula (1) (hereinafter sometimes referred to as "fluorosulfonylimide salt (1)") and a cyclic carbonate-based solvent or a cyclic ester-based solvent as main components By using the material, it is possible to suppress the temperature rise that causes decomposition of the non-aqueous electrolyte, and it is unnecessary to adjust the addition rate of the fluorosulfonylimide salt (1) when preparing the non-aqueous electrolyte. , can improve productivity. Therefore, according to the method of the present invention, a fluorosulfonylimide salt-containing non-aqueous electrolyte having good quality can be produced in a shorter time than the conventional production method.

The present inventors have conducted repeated studies to provide a method for efficiently producing a non-aqueous electrolytic solution containing the fluorosulfonylimide salt (1), which has better quality than conventional ones. By using an electrolytic solution material containing imide salt (1) and a cyclic carbonate-based solvent or a cyclic ester-based solvent as main components as a starting material for a non-aqueous electrolytic solution, the electrolytic solution Even if a solvent for electrolyte preparation and other electrolyte salts are added to the material, deterioration of the non-aqueous electrolyte due to heat generation is suppressed, and the non-aqueous electrolyte can be prepared in a shorter time than before while maintaining good quality. We found that it can be manufactured, and completed the present invention.

First, the circumstances leading to the present invention will be described. Conventionally, in the production of a non-aqueous electrolyte, a solvent solution is prepared in advance by mixing all the solvents used for electrolyte preparation, such as ethylene carbonate, methyl ethyl carbonate, and diethyl carbonate, and then a fluorosulfonylimide salt (1) or the like is added thereto. Electrolyte salts were added. When preparing the solvent solution, since ethylene carbonate is solid at room temperature, it is heat-treated to a temperature exceeding the melting point of ethylene carbonate (usually above 50° C.) before being mixed with another solvent for preparing an electrolytic solution. Therefore, the temperature of the solvent solution is high when adding the fluorosulfonylimide salt (1), and when the fluorosulfonylimide salt (1) is added, the liquid temperature rises to 60 ° C. or higher due to an exothermic reaction, resulting in a non-aqueous The electrolyte has deteriorated. Conventionally, as a means to solve such problems, it was necessary to control the temperature rise by controlling the addition rate of the fluorosulfonylimide salt (1). It takes a long time, the productivity is bad, and it is a factor of cost increase.

Therefore, as a result of the present inventors' investigation of the manufacturing process of the non-aqueous electrolytic solution, if an electrolytic solution material containing a fluorosulfonylimide salt (1) prepared in advance and a cyclic carbonate solvent or a cyclic ester solvent as main components is used, The heat treatment of a solid cyclic carbonate-based solvent or cyclic ester-based solvent, which was conventionally required in the manufacturing process of a non-aqueous electrolyte, is no longer necessary. By adding a solvent for preparing the aqueous electrolyte solution and an electrolyte salt, even if an exothermic reaction occurs due to the addition of these, the liquid temperature does not rise to a temperature at which decomposition of the electrolyte solution occurs. The inventors have found that it is possible to prepare a non-aqueous electrolytic solution in a short period of time without controlling the addition rate of the electrolyte salt for controlling the temperature, and have completed the present invention.

The term "fluorosulfonylimide" in the present invention includes di(fluorosulfonyl)imide having two fluorosulfonyl groups, N-(fluorosulfonyl)-N- (Fluoroalkylsulfonyl) imides are included.

The production method of the present invention is a method for producing an electrolyte material containing the fluorosulfonylimide salt represented by the general formula (1) and a solvent, wherein a solution containing the fluorosulfonylimide salt and the electrolyte solvent is decompressed and It is characterized by volatilizing the production solvent of the fluorosulfonylimide salt by heating (hereinafter sometimes referred to as a volatilization step). The solvent for producing the fluorosulfonylimide salt is the solvent used in the production of the fluorosulfonylimide salt, the solvent contained in the fluorosulfonylimide salt obtained by the conventional production method, and is synonymous with the residual solvent. be.

Compounds represented by the general formula (1) include compounds in which R ₁ has fluorine or a fluorinated alkyl group having 1 to 6 carbon atoms. The fluorinated alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. Specific fluorinated alkyl groups having 1 to 6 carbon atoms include, for example, fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, difluoroethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, 3,3,3-trifluoropropyl group, perfluoro-n-propyl group, fluoropropyl group, perfluoroisopropyl group, fluorobutyl group, 3,3,4,4,4-pentafluorobutyl group, perfluoro-n-butyl group, perfluoroisobutyl group, perfluoro-t-butyl group, perfluoro-sec-butyl group, fluoropentyl group, perfluoropentyl group, perfluoroisopentyl group, perfluoro-t-pentyl group, fluorohexyl group, perfluoro -n-hexyl group, perfluoroisohexyl group and the like. Among these, R ₁ is preferably fluorine, trifluoromethyl group, pentafluoroethyl group or perfluoro-n-propyl group, more preferably fluorine, trifluoromethyl group or pentafluoroethyl group.

R ₂ is a cation constituting the compound (1) and represents an alkali metal ion. Alkali metal elements include lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium and potassium, more preferably lithium.

Specific compounds represented by the general formula (1) include lithium di(fluorosulfonyl)imide, sodium di(fluorosulfonyl)imide, lithium(fluorosulfonyl)(trifluoromethylsulfonyl)imide, sodium(fluorosulfonyl)( trifluoromethylsulfonyl)imide, lithium(fluorosulfonyl)(pentafluoroethylsulfonyl)imide, and the like. More preferred are lithium di(fluorosulfonyl)imide and lithium(fluorosulfonyl)(trifluoromethylsulfonyl)imide.

In the present invention, the method for synthesizing the fluorosulfonylimide salt represented by compound (1) is not particularly limited, and all conventionally known methods can be employed. For example, WO 2011/149095, JP 2010-189372, JP 8-511274, WO 2012/108284, WO 2012/117961, WO 2012/118063 , JP-A-2010-280586, JP-A-2010-254543, JP-A-2007-182410, and International Publication No. 2010/010613.

The method for producing an electrolytic solution material containing the fluorosulfonylimide salt represented by the general formula (1) and an electrolytic solution solvent of the present invention comprises reducing the pressure and/or heating a solution obtained by mixing the fluorosulfonylimide salt and the electrolytic solution solvent. and volatilizing the solvent for producing the fluorosulfonylimide salt. As described above, even if the fluorosulfonylimide salt is isolated as a powder (solid), the powder contains the solvent used before isolation (hereinafter referred to as residual solvent or manufacturing solvent). The concentration of the production solvent can be reduced by reducing the pressure and/or heating the solution in which the fluorosulfonylimide salt is dissolved in the electrolyte solvent to volatilize the production solvent of the fluorosulfonylimide salt. Further, the method for producing an electrolytic solution material of the present invention includes adding an electrolytic solution solvent to a solution obtained by producing or refining a fluorosulfonylimide salt (a solution containing a fluorosulfonylimide salt and a solvent), and then reducing the pressure and / or The production solvent may be volatilized by heating, and after producing the fluorosulfonylimide salt by this method, an electrolytic solution material containing the fluorosulfonylimide salt and the electrolytic solution solvent can be produced.
Since the electrolyte solvent has a higher affinity and a higher boiling point than the residual solvent for the compound (1), the residual solvent can be efficiently volatilized and removed by reducing pressure and/or heating.

The residual solvent in the present invention includes the solvent used in the production reaction of compound (1), the solvent used in the purification step, and the like. When classified according to the affinity between the residual solvent and the electrolyte solvent described below, for example, the solvent having a medium affinity for the compound (1) includes water; alcoholic solvents such as methanol, ethanol, propanol and butanol; formic acid, Carboxylic acid solvents such as acetic acid; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone; Nitrile solvents such as isobutyronitrile, acetonitrile, valeronitrile, and benzonitrile; Ethyl acetate, isopropyl acetate, butyl acetate, etc. Ester solvents; diethyl ether, diisopropyl ether, t-butyl methyl ether, aliphatic ether solvents such as cyclopentyl methyl ether; Halogen solvents such as HF; Nitromethane, nitro group-containing solvents such as nitrobenzene; Ethylformamide, N- Nitrogen-containing organic solvents such as methylpyrrolidone; dimethylsulfoxide; and glyme-based solvents. Among them, acetonitrile, valeronitrile, ethyl acetate, isopropyl acetate, butyl acetate and cyclopentyl methyl ether are preferred. Solvents with low affinity for the compound (1) include toluene, o-xylene, m-xylene, p-xylene, benzene, ethylbenzene, isopropylbenzene, 1,2,3-trimethylbenzene, 1,2,4- Aromatic hydrocarbon solvents such as trimethylbenzene, 1,3,5-trimethylbenzene, tetralin, cymene, methylethylbenzene, 2-ethyltoluene, chlorobenzene, dichlorobenzene; pentane, hexane, heptane, octane, decane, dodecane, undecane , tridecane, decalin, 2,2,4,6,6-pentamethylheptane, isoparaffin (e.g., "Marcazol R" (Maruzen Petrochemical Co., Ltd. 2,2,4,6,6-pentamethylheptane, 2 , 2,4,4,6-pentamethylheptane), "Isopar® G" (C ₉ -C ₁₁ mixed isoparaffins from ExxonMobil), "Isopar® E" (ExxonMobil C ₈ -C ₁₀ mixed isoparaffins) chain aliphatic hydrocarbon solvents such as dichloromethane, chloroform, 1,2-dichloroethane; cyclohexane, methylcyclohexane, 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 4-dimethylcyclohexane, ethylcyclohexane, 1,2,4-trimethylcyclohexane, 1,3,5-trimethylcyclohexane, propylcyclohexane, butylcyclohexane, "Swaclean 150" (a mixture of C9 alkylcyclohexane manufactured by Maruzen Petrochemical Co., Ltd. ), aromatic ether solvents such as anisole, 2-methylanisole, 3-methylanisole, 4-methylanisole, etc. These solvents may be used alone. , or a mixture of two or more of them: toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, isopropylbenzene, 1,2,4-trimethylbenzene, hexane, heptane, chlorobenzene, dichlorobenzene, Dichloromethane and 1,2-dichloroethane are preferred.

The electrolyte solvent in the present invention has a higher affinity with the compound (1) than the residual solvent, can be suitably used in the volatilization step, and can be used as it is as an electrolyte material. . By using such an electrolytic solution solvent, the residual solvent can be removed efficiently. Furthermore, the electrolytic solution material of the present invention can be used as it is as an electrolytic solution for lithium secondary batteries by mixing necessary solvents, additives, electrolytes, and the like. The electrolyte solvent to be used may be appropriately selected from the affinity between the electrolyte solvent and the compound (1), the affinity between the residual solvent and the general formula (1), the boiling point of each solvent, and the like. For example, solvents having a high affinity with the compound (1) include carbonate-based solvents such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate; dimethoxymethane, 1,2-dimethoxyethane, and the like. Cyclic ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane and 4-methyl-1,3-dioxolane; Cyclic ester solvents such as γ-butyrolactone and γ-valerolactone sulfolane solvents such as sulfolane and 3-methylsulfolane; and N,N-dimethylformamide, dimethylsulfoxide, N-methyloxazolidinone and the like. These solvents may be used alone or in combination of two or more. Among the solvents exemplified above, carbonate-based solvents such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate (especially cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate) and γ-butyrolactone , and γ-valerolactone are preferred.

In the method for producing the electrolyte material of the present invention, the solution used in the volatilization step can be prepared by mixing the powder of the fluorosulfonylimide salt represented by the general formula (1) with the electrolyte solvent. I can. Alternatively, the fluorosulfonylimide salt represented by the general formula (1) may be produced and purified in a solvent, and an electrolyte solvent may be mixed with the resulting solution to perform the volatilization step.

In the method for producing an electrolyte material of the present invention, the amount of residual solvent contained before the volatilization step is not particularly limited with respect to the lower limit, but with respect to 100 g of the fluorosulfonylimide salt represented by the above general formula (1), For example, it is preferably 1000 g or less, more preferably 100 g or less, still more preferably 10 g or less, and most preferably 1 g or less. A large amount of residual solvent is not desirable because the amount of electrolyte solvent used increases and the time required for volatilization increases. When the solution obtained by producing and purifying the fluorosulfonylimide salt in the solution is used in the volatilization step, the solvent is distilled off before the volatilization step (before adding the electrolyte solvent) to remove the residual contained It is preferable to reduce the amount of solvent and make the amount of residual solvent within the above range.

In the method for producing the electrolyte material of the present invention, the amount of electrolyte solvent used is not particularly limited as to the lower limit, and may be appropriately adjusted depending on the amount of residual solvent and the like. For example, with respect to 100 g of the fluorosulfonylimide salt represented by the general formula (1), it is preferably 10000 g or less, more preferably 1000 g or less, still more preferably 500 g or less, still more preferably 200 g or less, still more preferably 100 g or less, Most preferably, it is 50 g or less.
In the method for producing the electrolyte material of the present invention, the amount of the electrolyte solvent used is preferably 1 to 1000 parts by mass with respect to 100 parts by mass of the fluorosulfonylimide salt represented by the general formula (1), More preferably 5 to 500 parts by mass, still more preferably 10 to 300 parts by mass, particularly preferably 30 to 200 parts by mass, and even more preferably 50 to 100 parts by mass.

The volatilization step may include a step of reducing the pressure and/or heating the fluorosulfonylimide salt represented by the general formula (1) and the electrolyte solvent, and can be carried out under normal pressure or under reduced pressure. From the viewpoint of preventing thermal decomposition of the fluorosulfonylimide salt, it is desirable to carry out the reaction under reduced pressure. The degree of pressure reduction may be appropriately adjusted according to the type of residual solvent and the type of electrolyte solvent, and is not particularly limited. and particularly preferably 5 kPa or less.

The volatilization temperature is not particularly limited and may be appropriately adjusted depending on the degree of pressure reduction, the type of residual solvent, and the type of electrolyte solvent, but it is performed at a relatively low temperature in order to prevent decomposition of the fluorosulfonylimide salt due to heat. is desirable. For example, it is preferably 10 to 110°C, more preferably 15 to 80°C, even more preferably 20 to 60°C, and particularly preferably 30 to 50°C.

The volatilization time is not particularly limited and may be appropriately adjusted according to the degree of pressure reduction, heating temperature, amount of residual solvent, etc., but is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours, More preferably 1 to 8 hours, particularly preferably 2 to 5 hours.

The apparatus capable of depressurization and/or heating used in the volatilization step may be appropriately selected according to the amount of solution, degree of decompression, heating temperature, and the like. For example, a tank reactor, a pressure-reduced tank reactor, and the like can be mentioned.

The concentration of the fluorosulfonylimide salt represented by the general formula (1) contained in the electrolyte material is not particularly limited and may be appropriately adjusted according to the type of the electrolyte solvent. is preferred, more preferably 20 to 90% by mass, and still more preferably 30 to 90% by mass. When the non-aqueous electrolyte is produced by adding an organic solvent to the electrolyte material, the electrolyte salt concentration in the non-aqueous electrolyte can be appropriately set. The concentration of the represented fluorosulfonylimide salt is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass or more. Since the concentration of the fluorosulfonylimide salt represented by the general formula (1) is 30% by mass or more, the electrolyte material of the present invention has good stability and causes corrosion of containers used for storage and transportation. Since generation of (hydrofluoric acid) is suppressed, it is also suitable for storage and transportation of the fluorosulfonylimide salt represented by the general formula (1).

As the electrolyte solvent contained in the electrolyte material of the present invention, the electrolyte solvent described above can be used. It preferably contains a cyclic ester solvent. Among them, ethylene carbonate or γ-butyrolactone is preferable, and ethylene carbonate is particularly preferable. The above cyclic carbonate or cyclic ester solvent is preferably contained in an amount of 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass or more, based on the total amount of the electrolyte solvent.

The amount of residual solvent in the electrolyte material is not particularly limited and may be appropriately adjusted according to the concentration of the residual solvent in the electrolyte material, but is preferably 3000 ppm or less, more preferably 2000 ppm or less, and still more preferably 1000 ppm. Below, particularly preferably 500 ppm or less, most preferably 200 ppm or less. When the residual amount of the production solvent for the fluorosulfonylimide salt contained in the electrolytic solution is within the above range, the amount of solvent in the obtained non-aqueous electrolytic solution can be suppressed, so the non-aqueous electrolytic solution was used. In the battery, side reactions during driving are suppressed, and swelling of the battery can be suppressed.

After completion of the volatilization step, filtration, column purification, activated carbon treatment, molecular sieve treatment, etc. may be performed as necessary.

Electrolyte materials obtained by the production method of the present invention include batteries having a charge/discharge mechanism such as primary batteries, lithium ion secondary batteries, and fuel cells, electrolytic capacitors, electric double layer capacitors, solar cells, electrochromic display elements, and the like. It is suitably used as a material for an ion conductor constituting an electrical storage device (electrochemical device).

The present invention also includes a non-aqueous electrolyte obtained using the electrolyte material and a method for producing a non-aqueous electrolyte using the electrolyte material. A non-aqueous electrolytic solution can be obtained by mixing a non-aqueous electrolytic solution-preparing solvent with the above electrolytic solution material, if necessary. Various electrolytes, additives, etc. may be added to the non-aqueous electrolyte for the purpose of improving battery characteristics, and a solvent suitable for dissolving the electrolyte may be added to the electrolyte material. A non-aqueous electrolyte can be prepared by adding a desired solvent to .
Therefore, the solvent for preparing the electrolytic solution is not particularly limited as long as it is compatible with the electrolytic solution solvent and dissolves and disperses the desired electrolytic salt. Further, in the present invention, conventionally known solvents used in batteries, such as non-aqueous solvents and media such as polymers and polymer gels used in place of solvents, can be used. The electrolyte solvent contains the electrolyte solvent, but if necessary, the same solvent as the electrolyte solvent may be added to the electrolyte material, and any of the electrolyte solvents described above may be used. can be done. The solvent for electrolyte preparation may be liquid or solid, but liquid is preferred for efficient mixing. Also, the temperature of the solvent for preparing the electrolytic solution is not particularly limited.

Among the solvents for preparing the electrolytic solution, carbonic acid esters (carbonate-based solvents) such as chain carbonic acid esters and cyclic carbonic acid esters, lactones, and ethers are preferable, and dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, More preferred are propylene carbonate, γ-butyrolactone and γ-valerolactone, and more preferred are carbonate solvents such as dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate. One of the above solvents may be used alone, or two or more thereof may be used in combination.

In the present invention, an electrolyte salt different from the fluorosulfonylimide salt (1) (hereinafter sometimes referred to as "another electrolyte salt") may be mixed with the electrolyte material, if necessary. The other electrolyte salt may be added to the electrolyte material before the electrolyte preparation solvent is added, but considering the dissolution efficiency of the other electrolyte salt, after adding the electrolyte preparation solvent to the electrolyte material Adding other electrolyte salts may be desirable. For example, when the other electrolyte salt to be added is poorly soluble in ethylene carbonate such as LiPF ₆ , a solvent suitable for dissolving the electrolyte salt is added to the electrolyte material as the electrolyte preparation solvent, and then the electrolyte salt is added. It is desirable to add

Other electrolyte salts are not particularly limited, and any conventionally known electrolytes used in electrolyte solutions for lithium ion secondary batteries can be used. For example, other electrolyte salts include trifluoromethanesulfonate (CF ₃ SO ₃ ⁻ ), fluorophosphate (PF ₆ ⁻ ), perchlorate (ClO ₄ ⁻ ), tetrafluoroborate (BF ₄ ⁻ ). , hexafluoroarsenate ion (AsF ₆ ^- ), tetracyanoborate ion ([B(CN) ₄ ] ^- ), tetrachloroaluminum ion (AlCl ₄ ^- ), tricyanomethide ion (C[(CN) ₃ ] ^- ), dicyanamide ion (N[(CN) ₂ ] ⁻ ), tris(trifluoromethanesulfonyl)methide ion (C[(CF ₃ SO ₂ ) ₃ ] ⁻ ), hexafluoroantimonate ion (SbF ₆ ⁻ ) and dicyanotri Conventionally known electrolyte salts such as inorganic or organic cation salts having anions such as azolate ions (DCTA) can be used. More specifically, LiPF ₆ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiBF ₄ and LiBF(CF ₃ ) ₃ are listed, with LiPF ₆ and LiBF ₄ being preferred, and LiPF ₆ being more preferred. By mixing the electrolyte material of the present invention with a solvent for electrolyte preparation and other electrolyte salts to produce a non-aqueous electrolyte, heat generation during mixing of the electrolyte salt can be suppressed. Decomposition can be suppressed, and an electrolytic solution of good quality can be obtained.

The nonaqueous electrolyte according to the present invention may contain additives for the purpose of improving various characteristics of the lithium ion secondary battery. The additive may be added at any stage of the manufacturing process of the non-aqueous electrolytic solution, and is not particularly limited. For example, it may be added after adding the electrolyte salt.

The present invention also includes methods for storing and transporting the electrolyte material of the present invention. The electrolyte material of the present invention contains a fluorosulfonylimide salt represented by the general formula (1) and an electrolyte solvent, and the concentration of the fluorosulfonylimide salt represented by the general formula (1) is 30% by mass or more. As a result, the stability is good and the generation of HF (hydrofluoric acid), which causes corrosion of containers used for storage and transportation, is suppressed, so the fluorosulfonylimide salt represented by the general formula (1) can be stored and Also suitable for transport. The concentration of the fluorosulfonylimide salt represented by general formula (1) in the electrolyte material is preferably 35% by mass, more preferably 40% by mass or more, and still more preferably 50% by mass or more. The upper limit of the concentration is preferably 95% by mass or less, more preferably 90% by mass or less. If the concentration of the fluorosulfonylimide salt represented by general formula (1) in the electrolyte material is less than 30% by mass, the decomposition of the fluorosulfonylimide salt generates an acid such as HF, which corrodes the container. , the electrolyte material may deteriorate.

As for the container used for storing and transporting the electrolytic solution material of the present invention, there are no particular restrictions on the shape of the container, such as the size and material, and conventionally known knowledge can be referred to as appropriate. Small storage containers can be used to store small quantities of electrolyte materials synthesized in the laboratory. Also, in order to store a large amount of electrolyte material synthesized on an industrial level, a large storage container may be used.

As for the material of the storage container, for example, metal materials such as stainless steel and Hastelloy, fluorine-based resins such as polytetrafluoroethylene (PTFE), and the like can be used. Among others, the container is preferably made of stainless steel from the viewpoint of high withstand pressure. For the purpose of further improving the corrosion resistance of the storage container, it is preferable to coat the inner surface of the container made of the above materials such as metal with a resin. At this time, the resin used for coating is not particularly limited, but examples include polytetrafluoroethylene (PTFE), tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene/hexafluoropropylene copolymer ( Fluorinated resins such as FEP) and olefinic resins such as polypropylene are exemplified. Among them, PTFE is preferably used for coating from the viewpoint that the effect of improving the corrosion resistance is excellent. Here, the coating thickness of the resin coating is not particularly limited, but is preferably 10 to 3000 μm, more preferably 500 to 1000 μm. Furthermore, the storage container is preferably sealable, and examples of means for making the container sealable include a form in which a valve is provided in a portion of the container.

This application claims the benefit of priority based on Japanese Patent Application No. 2014-204815 filed on October 3, 2014 and Japanese Patent Application No. 2015-118065 filed on June 11, 2015 It is something to do. The entire contents of the specifications of Japanese Patent Application No. 2014-204815 filed on October 3, 2014 and Japanese Patent Application No. 2015-118065 filed on June 11, 2015 are referred to in this application. Incorporated for

The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and can be modified appropriately within the scope of the above and later descriptions. Of course, it is also possible to carry out the method using other methods, and all of them are included in the technical scope of the present invention.

[Residual solvent amount]
200 μl of a dimethyl sulfoxide aqueous solution (dimethyl sulfoxide/ultrapure water=20/80, volume ratio) and 2 ml of a 20% by mass sodium chloride aqueous solution were added to 0.05 g of the electrolyte material to prepare a measurement solution, which was placed in a vial and sealed. A headspace-gas chromatography system (“Agilent 6890”, manufactured by Agilent) was used to measure the amount of residual solvent contained in the electrolyte material.
Equipment: Agilent 6890
Column: HP-5 (length: 30 m, column inner diameter: 0.32 mm, film thickness: 0.25 μm) (manufactured by Agilent)
Column temperature conditions: 60°C (hold for 2 minutes), heat up to 300°C at 30°C/min, 300°C (hold for 2 minutes)
Headspace conditions: 80°C (held for 30 minutes)
Injector temperature: 250°C
Detector: FID (300°C)

Production Example 1 Production of lithium di(fluorosulfonyl)imide (LiFSI) 120 g of butyl acetate was added to a 500 mL PFA reaction vessel equipped with a stirrer and a cooler, and 16.1 g of di(chlorosulfonyl)imide ( 75 mmol) was added and dissolved by stirring. 4.45 g (82.5 mmol) of ammonium chloride was added to the obtained di(chlorosulfonyl)imide solution, and the mixture was stirred at 80° C. for 1 hour. 20.53 g (360 mmol) of ammonium acid fluoride NH ₄ F.HF was added to the di(chlorosulfonyl)imide solution, and stirring was continued at 80° C. for 4 hours.
After completion of the reaction, the reaction solution was cooled to room temperature, and solid content was removed by filtration. The filtrate was transferred to a separating funnel, and an aqueous solution prepared by dissolving 3.15 g (75 mmol) of lithium hydroxide monohydrate in 21 g of ultrapure water was added and mixed. After allowing to stand still, the aqueous layer was removed. An aqueous solution prepared by dissolving 1.57 g (37 mmol) of lithium hydroxide monohydrate in 11 g of ultrapure water was again added and mixed. After allowing to stand still, the aqueous layer was removed.
128 g of a solution containing 10 g of lithium di(fluorosulfonyl)imide in the organic layer was obtained. The obtained solution was heated at 50° C. and 1.5 kPa for 1 hour to volatilize the butyl acetate to obtain 30 g of a solution composed of 10 g of lithium di(fluorosulfonyl) and 20 g of butyl acetate. ^{In 19} F-NMR (solvent: deuterated acetonitrile) measurement, the amount of trifluoromethylbenzene added as an internal standard substance, the integrated value of the peak derived from this, and the integrated value of the peak derived from the target product By comparison, the amount of lithium di(fluorosulfonyl)imide contained in the organic layer was determined.

Example 1
7.56 g of diethyl carbonate was added and dissolved in 4.99 g of separately prepared lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane in a 50 ml eggplant flask. The solution was decompressed at 25° C. and 1 kPa for 3 hours to volatilize the solvent. As an electrolyte material, 11.64 g of a solution of lithium di(fluorosulfonyl)imide in diethyl carbonate was obtained. The resulting solution contained 83 ppm of butyl acetate, but no dichloromethane was identified. Dichloromethane, which has a low affinity for lithium di(fluorosulfonyl)imide, was reduced by the volatilization process.

Example 2
4.76 g of ethylene carbonate (EC) was added to 3.23 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane in a 25 ml eggplant flask and dissolved. The solution was decompressed at 25° C. and 1 kPa for 3 hours to volatilize the solvent. As an electrolyte material, 7.83 g of an ethylene carbonate solution of lithium di(fluorosulfonyl)imide was obtained. The obtained solution was confirmed to contain 85 ppm of butyl acetate and 40 ppm of dichloromethane.

Example 3
A solution of 10 g of lithium di(fluorosulfonyl)imide dissolved in 20 g of butyl acetate and 20 g of ethylene carbonate were added to a 100 ml eggplant flask. The solution was heated at 60° C. and 1.5 kPa for 8 hours under reduced pressure to volatilize the solvent. 28 g of an ethylene carbonate solution of lithium di(fluorosulfonyl)imide was obtained as an electrolyte material. The obtained solution was confirmed to contain 60 ppm of butyl acetate. Butyl acetate, which has a moderate affinity for lithium di(fluorosulfonyl)imide, could be reduced by the volatilization process.

Examples 4-1 to 7-5
Di(fluorosulfonyl)imide was prepared in the same manner as in Example 3 except that the solvent contained in the di(fluorosulfonyl)imide solution, the electrolyte solvent, the solution temperature, the degree of pressure reduction, and the heating time were as shown in Tables 1 to 4. An electrolyte material containing The table shows the amount of residual solvent in the resulting solution.

Examples 8-1 to 8-3
A solution of 10 g of lithium di(fluorosulfonyl)imide obtained in Production Example 1 and 20 g of butyl acetate was used, and the procedure of Example 3 was repeated except that the solution temperature, the degree of pressure reduction, and the heating time were as shown in Table 5. An electrolyte material containing di(fluorosulfonyl)imide was obtained. The table shows the amount of residual solvent in the resulting solution.

Examples 9-1 to 13-5
Di(fluorosulfonyl)imide was prepared in the same manner as in Example 3 except that the solvent contained in the di(fluorosulfonyl)imide solution, the electrolyte solvent, the solution temperature, the degree of pressure reduction, and the heating time were as shown in Tables 6 to 10. An electrolyte material containing The table shows the amount of residual solvent in the resulting solution.

Comparative example 1
In a vacuum dryer, 5 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane was spread on a petri dish and dried at 60° C. and 1 kPa for 12 hours, but the amount of residual solvent did not decrease.

Comparative example 2
5 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane was pulverized in a mortar. It was spread on a Petri dish and dried in a vacuum dryer at 60° C. and 1 kPa for 12 hours, but the amount of residual solvent did not decrease.

Example 15-1
5.00 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 5.10 g of EC was added and dissolved. The solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. An electrolyte material consisting of 5.00 g of LiFSI and 5.00 g of EC was obtained.
The amount of residual solvent in the electrolytic solution material immediately after preparation was 55 ppm for butyl acetate, 5 ppm for dichloromethane, 20 ppm for water, and 4 ppm for HF. This electrolyte material was stored in a stainless steel container at 60° C. for 30 days. HF in the electrolyte material after storage was 8 ppm.
4 ppm of HF was generated during storage, and when converted to the mass of lithium di(fluorosulfonyl)imide (LiFSI), it was 8 ppm/LiFSI-kg.
HF was quantified using an automatic titrator manufactured by Metrohm. Specifically, using a non-aqueous solvotrode electrode, neutralization titration was performed with a 0.01N sodium hydroxide/methanol solution, and the generated acid was converted to HF.

Example 15-2
5.00 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 1.98 g of EC was added and dissolved. This solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. A solution was obtained consisting of 5.00 g of LiFSI and 1.78 g of EC. 3.22 g of ethyl methyl carbonate (EMC) was added to this solution to obtain an electrolytic solution material. The amount of residual solvent in the electrolytic solution material immediately after preparation was 45 ppm for butyl acetate and 6 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Example 15-3
5.00 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 4.50 g of EC was added and dissolved. This solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. A solution consisting of 5.00 g LiFSI and 4.40 g EC was obtained. 0.6 g of EMC was added to this solution to obtain an electrolyte material. The amount of residual solvent in the electrolytic solution material immediately after preparation was 43 ppm for butyl acetate and 5 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Example 15-4
5.00 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 5.20 g of γ-butyrolactone (GBL) was added and dissolved. This solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. An electrolyte material consisting of 5.00 g of LiFSI and 5.00 g of GBL was obtained. The amount of residual solvent in the electrolytic solution material immediately after preparation was 85 ppm for butyl acetate and 9 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Example 15-5
6.20 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 4.00 g of EC was added and dissolved. This solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. An electrolyte material consisting of 6.20 g of LiFSI and 3.80 g of EC was obtained. The amount of residual solvent in the electrolytic solution material immediately after preparation was 78 ppm for butyl acetate and 7 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Example 15-6
6.20 g of lithium di(fluorosulfonyl)imide powder containing 208 ppm of butyl acetate and 4621 ppm of dichloromethane as residual solvents was placed in a 50 ml eggplant flask, and 1.50 g of EC was added and dissolved. This solution was heated at 60° C. and 1 kPa for 3 hours to volatilize the solvent. A solution consisting of 6.20 g LiFSI and 1.35 g EC was obtained. 2.45 g of EMC was added to this solution to obtain an electrolyte material. The amount of residual solvent in the electrolytic solution material immediately after preparation was 95 ppm for butyl acetate and 10 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Reference example 1
A solution of 5.00 g of LiFSI and 5.00 g of EC was obtained in the same manner as in Example 15-1. EC was further added to this solution to obtain an EC solution containing 10.2% by mass of LiFSI. The amount of residual solvent in this solution was 13 ppm for butyl acetate and 2 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

Reference example 2
A solution of 5.00 g of LiFSI, 1.78 g of EC, and 3.22 g of EMC was obtained in the same manner as in Example 15-2. Further, 13.88 g of EC and 25.12 g of EMC were added to this solution to obtain a solution containing 10.2% by mass of LiFSI. The amount of residual solvent in this solution was 14 ppm for butyl acetate and 1 ppm for dichloromethane. After that, the amount of HF before and after storage was measured in the same manner as in Example 15-1.

As shown in Table 11, when compared with Examples 15-1 to 15-6 in which the LiFSI concentration in the electrolyte material is 50% by mass or more, in the reference example, the LiFSI concentration in the electrolyte material is 10.2 mass. %, it can be seen that the amount of HF generated during storage is remarkable. From this, it was confirmed that the electrolyte material of the present invention having a predetermined amount or more of LiFSI has the effect of suppressing the generation of HF during storage.

Example A-1
An electrolytic solution material was obtained in the same manner as in Example 2, except that the amount of ethylene carbonate used was 4.60 g. 2.62 g of LiPF ₆ , 5.69 g of EC, and 18.40 g of ethyl methyl carbonate (EMC) were added to the obtained electrolyte material, and 9.3% by mass of lithium di(fluorosulfonyl)imide (0.6M ), a non-aqueous electrolytic solution of EC/EMC=3/7 (volume ratio) mixed solvent containing 67.5% by mass (0.6M) of LiPF ₆ was obtained. The amount of residual solvent in this non-aqueous electrolytic solution was 8 ppm of butyl acetate and 4 ppm of dichloromethane.

Example A-2
An electrolytic solution material was obtained in the same manner as in Example A-1, except that the conditions for volatilizing the residual solvent were 25° C., 40 kPa and 3 hours. The amount of residual solvent at this time was 96 ppm of butyl acetate and 308 ppm of dichloromethane. _LiPF6 in the same amount as in Example A-1, EC and EMC were added to the resulting electrolyte material, and LiFSI was 9.3% by mass (0.6M) and _LiPF6 was 67.5% by mass (0.6M). A non-aqueous electrolytic solution of EC/EMC=3/7 (volume ratio) of 6 M) mixed solvent was obtained. The amount of residual solvent in this non-aqueous electrolytic solution was 9 ppm of butyl acetate and 29 ppm of dichloromethane.

Example A-3
An electrolytic solution material was obtained in the same manner as in Example A-1, except that the conditions for volatilizing the residual solvent were 25° C., 100 kPa and 3 hours. The amount of residual solvent at this time was 150 ppm of butyl acetate and 1280 ppm of dichloromethane. _LiPF6 in the same amount as in Example A-1, EC and EMC were added to the resulting electrolyte material, and LiFSI was 9.3% by mass (0.6M) and _LiPF6 was 67.5% by mass (0.6M). A non-aqueous electrolytic solution of EC/EMC=3/7 (volume ratio) of 6 M) mixed solvent was obtained. The amount of residual solvent in this non-aqueous electrolyte was 19 ppm for butyl acetate and 119 ppm for dichloromethane.

Comparative Example A-1
An electrolytic solution material was obtained in the same manner as in Example A-1, except that the operation of volatilizing the residual solvent was not performed. The amount of residual solvent at this time was 208 ppm of butyl acetate and 4621 ppm of dichloromethane. _LiPF6 in the same amount as in Example A-1, EC and EMC were added to the resulting electrolyte material, and LiFSI was 9.3% by mass (0.6M) and _LiPF6 was 67.5% by mass (0.6M). A non-aqueous electrolytic solution of EC/EMC=3/7 (volume ratio) of 6 M) mixed solvent was obtained. The amount of residual solvent in this non-aqueous electrolytic solution was 17 ppm of butyl acetate and 430 ppm of dichloromethane.
As shown in Table 12, in Examples A-1 to A-3, the volume expansion of the batteries when stored at 60° C. for one month was about 0.03 to 0.06 ml, but Comparative Example A-1 The result was 0.21 ml. It was confirmed that, in a battery including a non-aqueous electrolyte using an electrolyte material with a reduced amount of residual solvent, swelling of the battery during charging and discharging of the battery can be suppressed.

Preparation of Laminated Lithium Ion Secondary Battery 1. Preparation of positive electrode sheet Positive electrode active material (LiCoO ₂ ), conductive aid 1 (acetylene black, AB), conductive aid 2 (graphite), and binder (polyvinylidene fluoride, PVdF) were mixed at a ratio of 92:2:2:4. and dispersed in N-methylpyrrolidone. The positive electrode mixture slurry was applied to an aluminum foil, dried and compressed to prepare a positive electrode sheet.

2. Preparation of negative electrode sheet A negative electrode active material (graphite), a conductive agent (VGCF), and a binder (SBR + CMC) were mixed at a mass ratio of 97:0.5:2.5, and this was mixed with N-methylpyrrolidone. The resulting negative electrode mixture slurry was prepared. Calculate the charge capacity of the positive electrode at 4.2 V charge, apply the negative electrode mixture slurry to the copper foil (negative electrode current collector) so that the lithium ion occluding capacity of the negative electrode/positive electrode charge capacity = 1.1, A negative electrode sheet was produced by drying and compressing.

3. Fabrication of laminated lithium-ion secondary battery An aluminum tab and a nickel tab are welded to the uncoated portions of each of the positive electrode sheet and the negative electrode sheet prepared above, and placed facing each other with a polyethylene separator sandwiched therebetween. to produce a wound body. The prepared wound body was sandwiched between aluminum laminate films that had been drawn to an appropriate depth and untreated aluminum laminate films, and the insides of the aluminum laminate films were respectively the above Examples A-1 to A-3 and Comparative Example A-1. was filled with the mixed solvent electrolyte prepared in 1. and sealed in a vacuum state to prepare a laminated lithium ion secondary battery with a capacity of 1 Ah.

4. Battery evaluation Specific capacity (mAh/g)
For the laminated lithium ion secondary battery, use a charge/discharge test device (ACD-01 manufactured by Aska Electronics Co., Ltd., hereinafter the same) in an environment at a temperature of 25 ° C., under predetermined charging conditions (0.5 C, 4.2 V , constant current and constant voltage mode) for 5 hours. After that, discharge is performed under predetermined discharge conditions (0.2 C, discharge final voltage 3.0 V, constant current discharge), the initial discharge capacity is recorded, and the mass specific capacity of the battery is calculated based on the following formula. Discharge characteristics were evaluated.
Mass specific capacity (mAh/g) = initial charge capacity of battery (mAh)/mass of positive electrode active material (g)

5. High-temperature storage characteristics After measuring the specific capacity, the laminated lithium-ion secondary battery was subjected to a charge-discharge test under a temperature of 25 ° C. After charging in voltage mode 0.02C cut), discharge under predetermined discharge conditions (0.2C, discharge end voltage 3.0V, constant current discharge), and then again under predetermined charging conditions (1C, 4.2V , constant current constant voltage mode 0.02C cut). The obtained cell was stored in a constant temperature bath at 60° C. for one month. The cells before and after storage were immersed in water to determine the volume, and the difference was used to obtain the swelling amount of the cell after storage. The results are shown in Table 12.

Example B-1
A non-aqueous electrolyte was produced by charging each material into the mixing vessel in the charging order shown in Table 13. In the table, LiFSI and EC whose charging order is 1 were used as electrolytic solution materials prepared in advance by mixing 11.22 kg of LiFSI and 36.36 kg of EC. After the electrolyte materials were put into a mixing pot (capacity 150 L), 27.82 kg of EMC as a solvent for electrolyte preparation, 35.81 kg of diethyl carbonate (hereinafter sometimes referred to as "DEC"), and LiPF ₆ ( Kishida Chemical Co., Ltd.) 9.12 kg was sequentially put into the mixing vessel, and then stirred for 10 minutes to obtain a non-aqueous electrolyte. It took 10 minutes to add the electrolytic solution materials, the solvents for preparing the electrolytic solutions, and the other electrolytic salts. In the table, "required time" is the time from the start of charging to the end of charging, and charging was performed while stirring. Table 1 shows the measured liquid temperature after each material was put into the mixing vessel. Temperature was measured in the same manner for other examples.

As shown in Table 13, the liquid temperature in the mixing vessel was measured during the manufacturing process of the non-aqueous electrolyte, but the temperature did not exceed 60°C. Specifically, no heat was generated when the electrolytic solution preparation solvent (EMC, DEC) was added to the electrolytic solution material. Although the temperature of the liquid after charging LiPF ₆ rose to 45° C., decomposition of the electrolyte did not occur.

Example B-2
A non-aqueous electrolyte was produced by charging each material into the mixing vessel in the charging order shown in Table 14. Specifically, an electrolyte material prepared by mixing 11.22 kg of LiFSI and 20.0 kg of EC was put into a mixing pot (capacity: 150 L), and then 27.82 kg of EMC and 35.81 kg of DEC were added as solvents for preparing the electrolyte solution. . After that, 16.36 kg of EC heated to 60° C. as a solvent for electrolyte preparation was added to the mixing pot, and then 9.12 kg of LiPF ₆ was added as another electrolyte salt, followed by stirring for 10 minutes to obtain a non-aqueous electrolyte. got It took 10 minutes to add the electrolytic solution materials, the solvents for preparing the electrolytic solutions, and the other electrolytic salts.

The liquid temperature in the mixing pot was measured during the manufacturing process of the non-aqueous electrolyte, but the temperature did not exceed 60°C. Specifically, no heat was generated when the electrolytic solution preparation solvent (EMC, DEC) was added to the electrolytic solution material. The liquid temperature after adding EC heated to 60° C. was 30° C., and the liquid temperature after adding LiPF ₆ was increased to 50° C. However, no decomposition of the electrolytic solution occurred.

Comparative Example B-1
A non-aqueous electrolyte was produced by charging each material into the mixing vessel in the charging order shown in Table 15. Specifically, 36.36 kg of the EC solution heated to 60° C. was put into a mixing vessel, and then 27.82 kg of EMC and 35.81 kg of DEC were put into the mixture to prepare a non-aqueous solvent solution. Subsequently, LiFSI was added, and 11.22 kg of LiFSI was added in 3 portions (3.74 kg/time) so that the liquid temperature did not exceed 55°C. Subsequently, 9.12 kg of LiPF ₆ was charged in 3 portions (3.04 kg/time). Stirring was performed for 10 minutes after charging to obtain a non-aqueous electrolyte. It took 10 minutes to add each electrolyte solution preparation solvent, LiFSI, and LiPF ₆ . The time required for adding LiFSI and LiPF ₆ is the total time (10 minutes once×3 times).

The liquid temperature in the mixing pot was measured during the manufacturing process of the non-aqueous electrolyte, but the temperature did not exceed 60°C. Specifically, no heat was generated when the electrolyte solution preparation solvents (EMC and DEC) were added to the EC solution, and the solution temperature after preparing the non-aqueous solvent solution was 40° C. (addition order 3). After that, LiFSI and LiPF ₆ were charged separately, so that the temperature rise was suppressed and the decomposition of the non-aqueous electrolyte did not occur. However, the addition of LiFSI and _LiPF6 took a long time, resulting in poor productivity.

Comparative Example B-2
A non-aqueous electrolyte was produced by charging each material into the mixing vessel in the charging order shown in Table 16. Specifically, after preparing a non-aqueous solvent solution (40° C.) in the same manner as in Comparative Example 1, 11.22 kg of LiFSI was added. Subsequently, 9.12 kg of LiPF ₆ was added. Stirring was performed for 10 minutes after charging to obtain a non-aqueous electrolyte. It took 10 minutes to add each electrolyte solution preparation solvent, LiFSI, and LiPF ₆ .

After LiFSI was added, the liquid temperature was 55°C, and after LiPF ₆ was added, the liquid temperature was increased to 75°C. The resulting non-aqueous electrolyte was colored light orange, indicating decomposition of the electrolyte.

From the results of Examples B-1 and B-2 and Comparative Examples B-1 and B-2, the following can be understood. As shown in Examples B-1 and B-2, an electrolytic solution material prepared by pre-mixing fluorosulfonylimide salt (1) and ethylene carbonate was used as a starting material, and a solvent for preparing an electrolytic solution and other electrolytes were added thereto. Even if salt was added and heat was generated, the liquid temperature was kept low. Therefore, the decomposition of the non-aqueous electrolyte was prevented, and a good quality non-aqueous electrolyte was obtained. Moreover, the time required to prepare the non-aqueous electrolytic solution was 50 to 60 minutes, and the production efficiency was superior to that of Comparative Example B-1.

On the other hand, in Comparative Example B-1, LiFSI and LiPF ₆ were charged separately in order to control the temperature so that the non-aqueous electrolyte would not decompose. As a result, although the temperature rise could be suppressed, the time required to prepare the non-aqueous electrolytic solution was lengthened (120 minutes), and the production efficiency was poor as compared with Examples B-1 and B-2.

In Comparative Example B-2, LiFSI and LiPF ₆ were added all at once without dividing after preparing the non-aqueous solvent solution. As a result, although the time required for preparing the non-aqueous electrolyte can be shortened, the temperature rise could not be suppressed, so the non-aqueous electrolyte was decomposed and colored.

From the above results, by using the electrolyte material of the present invention containing fluorosulfonylimide salt (1) and a cyclic carbonate-based solvent or a cyclic ester-based solvent as main components, the temperature rise during the manufacturing process can be appropriately controlled. As a result, the non-aqueous electrolytic solution can be effectively prepared in a shorter period of time than in the conventional method, while suppressing the decomposition of the non-aqueous electrolytic solution.

Electrolyte materials obtained by the production method of the present invention include batteries having a charge/discharge mechanism such as primary batteries, lithium ion secondary batteries, and fuel cells, electrolytic capacitors, electric double layer capacitors, solar cells, electrochromic display elements, and the like. It is suitably used as a material for an ion conductor constituting an electrical storage device (electrochemical device).

Claims (6)

An electrolytic solution material containing a fluorosulfonylimide salt represented by the following general formula (1) in which a first solvent is incorporated into powder, and an electrolytic solution solvent as a second solvent,
The first solvent includes water, alcohol solvents, carboxylic acid solvents, ketones, nitrile solvents, ester solvents, aliphatic ether solvents, halogen solvents, nitro group-containing solvents, nitrogen-containing organic solvents, dimethyl At least one selected from the group consisting of sulfoxides, glyme solvents, aromatic hydrocarbon solvents, chain aliphatic hydrocarbon solvents, cycloaliphatic hydrocarbon solvents, and aromatic ether solvents,
The second solvent is at least one selected from the group consisting of carbonate solvents, chain ether solvents, and cyclic ester solvents,
An electrolyte material, wherein the concentration of the fluorosulfonylimide salt is 30% by mass or more, and the total residual amount of the first solvent is 200 ppm or less.

(In general formula (1), R ₁ represents fluorine or a fluorinated alkyl group having 1 to 6 carbon atoms, and R ₂ represents an alkali metal ion.) An electrolytic solution material containing a fluorosulfonylimide salt represented by the following general formula (1) and an electrolytic solution solvent,
The electrolyte solvent is at least one selected from the group consisting of carbonate-based solvents, chain ether-based solvents, and cyclic ester-based solvents,
The solution containing the fluorosulfonylimide salt and the electrolyte solvent is depressurized and/or heated, and the residual solvent incorporated in the powder of the fluorosulfonylimide salt is volatilized and contained in the electrolyte material. wherein the concentration of the fluorosulfonylimide salt is 30% by mass or more, and the total residual amount of the residual solvent is 200 ppm or less.

(In general formula (1), R ₁ represents fluorine or a fluorinated alkyl group having 1 to 6 carbon atoms, and R ₂ represents an alkali metal ion.) The residual solvent includes water, alcohol solvents, carboxylic acid solvents, ketones, nitrile solvents, ester solvents, aliphatic ether solvents, halogen solvents, nitro group-containing solvents, nitrogen-containing organic solvents, dimethyl sulfoxide, It is characterized by being at least one solvent selected from the group consisting of glyme solvents, aromatic hydrocarbon solvents, chain aliphatic hydrocarbon solvents, cycloaliphatic hydrocarbon solvents, and aromatic ether solvents. The electrolyte material according to claim 2. The electrolyte material according to any one of claims 1 to 3, wherein the electrolyte solvent contains 90% by mass or more of a cyclic carbonate solvent or a cyclic ester solvent. A method for storing an electrolyte material, comprising storing the electrolyte material according to any one of claims 1 to 4. A method for transporting an electrolyte material, comprising transporting the electrolyte material according to any one of claims 1 to 4.